The rise of computerized trading strategies in equity markets has spurred competition between trading venues. This paper shows that cross-venue strategies create highly interlinked markets: trades on one venue are followed by sizeable cancellations of limit orders on competing venues. These cancellations are explained in a simple model of competition between two limit order markets with fast and slow traders. Only the fast traders can access the liquidity of both venues simultaneously. Empirically, we confirm the predictions that the fraction of fast traders (1) reduces the equilibrium liquidity supply and (2) reduces the magnitude of the cancellations following a trade.

The rise of computerized trading strategies in equity markets has spurred competition between trading venues. This paper shows that cross-venue strategies create highly interlinked markets: trades on one venue are followed by sizeable cancellations of limit orders on competing venues. These cancellations are explained in a simple model of competition between two limit order markets with fast and slow traders. Only the fast traders can access the liquidity of both venues simultaneously. Empirically, we confirm the predictions that the fraction of fast traders (1) reduces the equilibrium liquidity supply and (2) reduces the magnitude of the cancellations following a trade.

Two important characteristics of current equity markets are the large number of competing trading venues with publicly displayed order books and the substantial fraction of dark trading, which takes place outside such visible order books. This article evaluates the impact on liquidity of dark trading and fragmentation in visible order books. Dark trading has a detrimental effect on liquidity. Visible fragmentation improves liquidity aggregated over all visible trading venues but lowers liquidity at the traditional market, meaning that the benefits of fragmentation are not enjoyed by investors who choose to send orders only to the traditional market.